1. Field of the Invention
The present invention relates to panel production machinery, and, more particularly, to an installation for the production of layered pressed panels and decorative panels, or for the application of coated paper sheets, liners, veneer sheets, plastic films, etc., to panels of chipboard, fiber, metal, plastic, or plywood, the installation consisting essentially of a layer assembly unit, a press pack feeding unit, and a panel press.
2. Description of the Prior Art
In recent years, both the variety of pressed panels, in terms of their composition, and the application possibilities for such pressed panels have undergone rapid increase and growth. As competitive pressures dictate the search for ever greater production economies through mechanization, it becomes necessary to employ layer assembly units and press pack feeding units of increasing speed and efficiency, in order to fully utilize the capacity of a modern panel press of single-level or multi-level construction. At the same time, such an installation must be quickly adaptable to the production of a large variety of layered pressed panels and for the veneering, or application of overlay materials to carrier panels, for the production of veneer panels, panels of chipboard, fiber, or plywood construction panels, plastic panels, and even metal panels.
Known installations of this kind operate either semiautomatically or fully automatically, using vertically movable suction carriages, supported on overhead rails, which move over the layer stacks, pick up one layer at a time with the aid of suction heads, and carry it to an assembly table, where the layer is deposited. The assembled press pack is then transferred from the assembly table to a press pack feeding station, where it is introduced into the panel with a by means of a roller conveyor, or belt conveyor, or with the aid of transfer panels of sheet metal.
Another, more advanced layer assembly device is disclosed in U.S. Pat. No. 3,914,154, the device featuring a collecting carriage on overhead rails which moves from layer stack to layer stack on a row of stack tables. At the edge of each stack table is arranged a stationary edge lifting device with a vertically movable suction bank which raises the edge of the uppermost panel layer, while a horizontal collecting palette of the collecting carriage, with partially assembled press pack, slides under the raised layer.
In order to avoid damaging the thin panel layers during collection, particularly in the case of very large panel dimensions, it has become necessary to completely mechanize the layer collecting procedure. This means that complex and expensive machinery is required for the layer collection line, or lines, as well as for the press pack transfer unit which feeds the assembled layer packs to the panel press. Nevertheless, the time for assembling and transferring a complete press pack may be too long, in comparison to the pressing cycle of a modern panel press. This is particularly so in the case of layered pressed panels which may be composed of up to eight different layers, in order to obtain the desired coloring, surface pattern and/or mechanical characteristics, or in the case of chipboard panels which may have to be covered with up to three outer layers on each side. A similar discrepancy between the cycle duration of the press and that of the layer collecting and press pack transfer machinery exists, when the panel press is of the so-called rapid cycling type which is capable of pressing several successive press packs simultaneously.